Monthly Archives: October 2015

Seawater isotope ratios through time: sulfur and carbon

Cortney October 9, 2015 Science & Technology + carbon, isotopes, sea level, sulfur

Low sea levels = heavy carbon, light sulfur in seawater

Low sea levels = more land space for plants = plants use lighter carbon = lighter carbon stuck on land = heavy carbon in the sea!
Low sea levels = less habitat for sulfate-reducing bacteria = less light sulfur in pyrite = more light sulfur in the sea!

High sea levels = light carbon, heavy sulfur in seawater

High sea levels = less space for plants = less light carbon uptake by plants = light carbon in the sea!
High sea levels = expanded habitat for sulfate-reducing bacteria = more light sulfur in pyrite = less light sulfur in the sea!

Subducted seawater the source of fluid-rich diamonds

Cortney October 3, 2015 Science & Technology + diamonds, earth magazine, mantle, melting, subduction, tectonics

How the west was made: western North American orogenies

Cortney October 3, 2015 Science & Technology + geology, north america, rocky mountains, tectonics

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Western North America is a patchwork is hundreds of terranes, which are crustal pieces or microplates (think of islands), that collided with and attached to North America across hundreds of millions of years -- adding piece-by-piece to the continent's width and building mountains as they produced volcanoes or pushed up sediments and rocks. This posts provides a very simplified timeline of the major orogenies and terranes that affected western North America. For a more in-depth look, see the resources below. Read more →